No definitive cow death-swede link

Beef and Lamb southern South Island extension manager Paul McCauley
Beef and Lamb southern South Island extension manager Paul McCauley
There have been a couple of reports in South Otago. There is nothing to say it won't be in Otago.

Beef and Lamb southern South Island extension manager Paul McCauley. The working group set up to find the cause of cows falling ill and in some cases dying in Southland after eating swedes says there is no definitive link with the HT swede variety. Beef and Lamb southern South Island extension manager Paul McCauley said there was also evidence to suggest Otago was not free from problem.

''There have been a couple of reports in South Otago. There is nothing to say it won't be in Otago.''

The working group, which is made up of representatives from Southland veterinary practices, Federated Farmers, Beef and Lamb NZ and PGG Wrightson Seeds, met for the first time last week and would meet again today to discuss more results and surveys that had been circulated among farmers throughout the region.

Mr McCauley said the group believed a combination of factors caused the cows to fall ill. There had been reports of cows that had been grazing on different types of swede crops becoming ill and sometimes dying, he said.

Initial reports from veterinary advisers suggested glucosinolate toxicity was the cause of the illness.

Glucosinolates are natural components of many pungent plants, especially brassicas. Small amounts ingested by humans and animals are believed to contribute to the health-promoting properties of cruciferous vegetables.

PGG Wrightson Seeds general manager David Green said mild weather conditions in Southland this season meant there was more leaf on swedes and the bulb of the swede was less palatable, leading to higher ingestion of glucosinolates. Leaves of swedes contain much higher concentrations of glucosinolates than bulbs.

Another swede had also been associated with the issue, but there had been no reports of problems in other parts of the country with the HT swede variety, Mr Green said.

''This supported the view that a combination of the weather and other extenuating circumstances in Southland are behind the problem,'' he said.

Veterinary practices in Southland first noticed signs of unusual liver damage after doing autopsies of cows which had been feeding on swedes in July.

VetSouth managing director Mark Bryan said symptoms for cows that had eaten swedes in the region included photosensitivity, weight loss and/or ill thrift.

''Investigations are continuing and we have collected huge amounts of data from over 40 farms and are now helping DairyNZ to get more of the answers we need to address this problem.''

By Nicole Sharp 

 

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